Mold.



THOMAS SLOPER, OF DEVIZES, ENGLAND.

MOLD.

Specification of Letters Patent.

Patented'ept., 3T3, tul.

Application filed November 18, 1915. Serial No. $2,197.

1T@ ci] 107mm it may conce-Mz Be it known that l, THOMAS SLornn, a subject ot the King ot England, residing' at Devizes, in lViltshire, England, have invented certain new and usetnl mprovements in Molds, of which the following is a speciicatioir rThis invention is for improvements in or relating to molds and articles manufactured thereby, and has reference to the type of mold wherein one part is desired to etlect a pressing or sealing movement toward another after all the parts, as well as the inaterial to be treated or formed into an article, arein place.

The invention is particularly applicable to molds for vulcanizing rubber goods. lt is well-known that the material to be vulcanized to form the article, say, a thin band or lining for a pneumatic tire, is commonly built up on a circular former and to vulaiiiize the band, the former is placed inside a surrounding" mold-element wherevvith it cooperates to constitute a mold. rlhis surrounding mold portion is -made in two or more sections, and means are provided for advancing these sections forcibly toward the former so that the band is pressed between them and the cavity inV which it lies is sealed by the close contact ot the various parts of the mold with each other. This form of mold, however, has the disadvantage that the pressure isnot uniformly distributed and a mark is produced on the outside of the molded article at the point where any two sections of the mold join, so that lit would be of considerable advantage it the interior former and the surrounding mold-element could each be made in a single piece. This, however, has not up to the iresent been done as the article to be vulcanized ofi the toriner7 must pass with the former easily into the sur rounding mold-eleiiient, and pressure must be applied during vulcanization.

Another -method ot vnlcanizing articles on a former is to wrap the article and the former around with canvas to put the.

necessary pressure on the article to be vnlcanized. rlChis method has the vdiszuflvantage that tor producing cheap articles, the costot the canvas, which can only be used a few times, adds to the cost ot production, and further, a thin article is liable to bel distorted in the process of wrapping.

' ot one 4Jform ot' mold,

spective view of .another form of mold, part being broken away to show the cross-sec- This invention consists broadly in a mold wherein the parts (or the supports ot' such parts) between which the material to be treated is to be subjected to heat under pres sure as in the process of vulcanization, are composed of materials having considerablyldii'l'erent coetilcients Vof expansion and are so arranged that as the mold is heated the greateinexpansion of one part relatively to the other exerts the requisite pressure upon the material to be treated, with or without the arrangement being such that the expanding movementseals the material in the mold.

Preferably the expansible member of the mold, e. c. that part having the .greaterI coetlicient ot expansion, s entirely surrounded by the other part or member, and one ol these members may be recessed so that the two parts ot the mold may entirely close and seal the material to be treated, between them, i

when the mold is heated sutliciently for the required expansion to talre place.

The expansible member n eed not be solid,

c. all composed ot' one'material. It may be a composite member comprising foreiganiple a ring of material having a high coefficient oit' espansiomsay, zinc, 'carried by a support made of a less expensive material, say, iron, whose coelcient of be less than that ot' the part it supports.

' In the accompanying drawings which illustrate two methods of invention:-Figure l is a transverse section and Fig. 2 is a pertional form.

expansion may carrying out this,

i The outer member A of the mold may be y of cast iron and is in the form of a ring having a. smooth inner molding face A1 and an inwardly-directed side iiange A2. rfhe inner or expansible member B is of zinc or other material, or mixture of materials, wliichhas a high coefficient ot' expansion relatively to the material ot the outer member. rIhis eX- n pa nsible member is also in the form of a ring and its'peripheral tace B1. is channeled or grooved at B2 to receive a band C (herein- 'at'termorefully described) which yis to be vulcanized. y It is found that flt, with the parts A and B made in the formand the proportions shown. the circumference of thevrinof. B

being about 6 feet and a clearance between the. Opposing faces A1,' 131 ot twenty-fiveand the channel in which the band lies setl'ectually sealed by the' -face B1 being forced against the face A1. When treating a thin band, such as C, (and the process is not suitable for thick articles) this sealing is not essential, so that the faces B1, A1 .need not be made to come into close contact, and in fact the channel B2 may be dispensed with, the size of the ring B being made such that it can, with the band on its periphery, be easily dropped into place, and then when it expands will exert the requisite pressure on 'the band. The flange A2 constitutes a convenient shoulder against which the member 'B rests when dropped ,into place and enables the two parts to be readily handled by grasping the outer part only, and thus no fastenings are required between these two parts. As a zinc ring` is liable toA get damaged in use the said eX- pansible member instead of being solid as shown in Fig. l, may be a composite inember as shown in Fig. :2. In this figure, the outer member is the same as in Fig. 1, hut the zinc or other expansible body is in the form of a ring l) of approximately V- shaped cross-section and is carried in an approximately V shaped trough D provided inra ring lll. The inner faces of the trough D2 at the outer edges D3 are parallel and the corresponding portions of the Zinc l) are parallel. The ring D vis made to a loose lit in the trough and is centered radially therein by compressible packing composed for example of one or more cords of asbestos E, placed at the bottom of the trough.

lit is found that if a ring` such as l) be mounted A he made a tight lit therein, it is liable to fracture in cooling, because it cools more 'ckly than the iron support whereas if ie ring D be so vmounted as to have a l sure of tree playin the trough D2 of 'i D1 as described, it exerts all the cees. iy pressure on the band C, and as it can expand and contract freely in all directions it does not break. ,".lhe packing E although centering the ring yields to pres# sure and therefore does not break it and the sides of the ring and trough are made a sufficiently close lit, especially at D3, to keep from 1nucl-:ling laterally without so tight as to cause it to jam when be seen that with this` forni of 'expansibe n einher, the groove or channel for C is provided by making the in an iron channeled member and masses part D smaller in diameter than 'the part D1, and this latter need only be made a sliding lit in the n'ieinber A as both and D1 may be of the same material, say, cast iron.

The ring D1 isniade ot' two parts secured 'together by bolts and nuts l", whereof only one of the bolts is shown. Obviously the ring A and eren the rings i3 and D may be built up otmore than one part if desirer, provided no parts in any one element in contact with the material are inoyabl'e relatively to one another to bring pressure to hear on the material to be molded. lt will be appreciated that mold members made up of several. parts can he accurately joined even at he molding faces, so that no projection or roughness will appear on the .molded goods, but this is not the case when the separate movement oi such mold parts is depended upon to exert the requisite pressure. This invention, therefore, includes mold members built up oiZ several parts, but does not apply to those wherein a plurality oi' parts composing the moli'ling faces are mechanically moyable in or out to exert pressure on the material to be molded.

These molds are particularly suited for making endless tapes or bands, such as are employed in cigarette manufacturing niachines. lt is necessary 'that the exterior oi' these bands shall be quite free voit any transverse projections or roughnesses as the bands are drawn through diesin the 1nachines, and such projections tend to consid erably decrease the life ci the band, bef' cause the band would be subjected to greater wear at these lparts, and also each projection causes increased tension von the band vas the portion lhaving the projection ou it passes through a die and a certain amount of tugging results. rlhe bands shown at C are fr this purpose, and are built up of thin longitudinal cords placed side by side and covered with a wrapping ot' r'ine rulr bered canvas. The com}' osition of the bands constitutes no part or" the vpresent invention, which is onlv tor the mold or any article vulcanized therein'. The invention is, however, particularly suited to the molding of cigarette machine bands or tapes as the said 1 inner mesma oly higher coeiiicient of expansion than the outer part,so` that when the mold is heated theinner part expands and presses the material to be treated against the opposing face of the outer part, r

substantially as set forth.-

ln a mold for applying pressure to material while it is heated as in 'vulcanizing, the combinationu of an inner. part, and an outer part which ner part but leaves` a space between the two parte to receive the material to be treated, one of the parts moreover being recessed to receive the material, aiid the said'inner part lbeing made of a metal having a considerably higher coefficient of expansion than the outer part so that when the mold is heated the inner part expands and the material to be treated is thus pressed into the recess and 'the recess is sealed by its edges being brought to bear against the non-recessed portion ot that mold part opposed to it, substantiallv as set forth.

el. In a mold for applying material while it is heatedas in the combination of an outer annular inembei', and an inner circular member Whose coefficient of expansion is considerably higher than that of the outer member, which inner member receives the material to be treated on its periphery and whose diameter' is such that it can be placed easily within the outer member with the material on it, but is big enough so that when heated it will expand suiiiciently to press the material firmly against the outer member, substantially as set forth.

5. ln a mold for applying pressure to material while it is heated as in vulcanizing, the combination of an outer annular member, and an inner circular member whose coeiieient of expansion is considerably higher than that of the outer member, which inner member has a peripheral chan` vnel to receive the material to be treated and whose diameter is such that it can be placed easily within the outer member with the material on it, but is big` enough so that when heated it will expand sufficiently to press the material firmly against the outer member, substantially as set forth.

(3. ln a mold fog/applying pressure 'to pressure to parts arranged substantially asV as in vulcanizing,

entirely encircles the in vulcanizing,

`ber of comparatively hard n the two parts, and means for .when the mold is heated material while it is heated as in vulcanizing, 'the combination of an outer annular member of comparatively' hard' metal, an inner ringof comparatively soft metal having a coefficient of expansion higher than that of the outer member, and a supporting ele- 'ment of harder metal mounted as a backing for the inner ring, the diameter ot'thecom-A posite inner element thus provided being such that the inner element can be dropped` into the outer element with the material to be treated placed on the periphery of thc former, but vwhen the inner element will expand sufficiently to force the material against the opposing face l of the outer element, substantially as set forth.

7: In a mold for applying pressure to material while it is heated as in vulcanizing,

combination of, an outer annular memthe ber of comparatively hard metal, 'an in ner ring of comparatively soft metalhaving a coefficient of expansion considerably higher than that of theouter member, and

a supporting element of harder metal havnig a peripheral trough 1n which the ring'of softer metal lies, the diameter ofthe vcomposite inner element thus provided being such that the inner element-can be dropped into the outer element with be treated placed on theperiphery of the former, but when the mold is heated the inner element will'expand sufficiently to' force the material against the opposing face of the outer element substantially as set forth. 100

8, In a mold for applying pressure to m terial while it 1s heated as in vulcanizin the combination of an outer annular memring of comparatively soft ooetlicient of expansion considerably higher than that of the outer member, a supporting element of harder metal having a peripheral ltrough to receive the ring of softer metalA and divided in the longitudinal the trough for admitting the ring between securing the two parts together with the ring vbetween them, the diameter of the composite inner clement thus provided being suchthat the f15'- inner element can be dropped into the outer element with the material to .be treated; placed on the periphery of the former, but the inner element will expand suiiiciently to force the'mgte rial against the opposing face of thewutei element, substantially as set forth.

9. In a mold for applying pressure to 'material while it is heated as in vulcanizing, the combination of an outer ber of comparatively hard metal, an inner ring ofcomparatively soft metal havingA a coefficient of expansion considerably higher than that 'of the outer member, element of harder mold is heated the the material to `letal, an inner; metal having a direction of 1.10

annular mema supporting metal having a periph- 13'0 eral trough to receive the ring of softer metal, the trough being of such depth that its bottom is free of the bottom or inner pe-l riphery of the ring, and means for centering the ring radially in the trough, the diameter of the composite inner element thus provided being such that the inner element can be dropped into the outer element with .the material to be treated placed on the periphery of the former, hut when the mold is heated the inner element will expand suiiii ciently to force the material againetthe` oposing face of the outer element3 suostantially as set forth. -10 In a mold for applying pressure to material While it is heated as in vuleanizing, the combination oi an outer annular nie1nber oli' comparatively hard inetal, an inner ring of coinparatirely soft inetal haring eoelieient of expansion considerably higher than that of the outer nieiiiber, a supporting element on harder .metal having a peripheral trough to reeeive the ring of softer metal, the trough being of sii'ch depth that its `bot toni is free ofthe bottoni or inner periphery of the ring, and eonipressihle packing' placed :between the bottoni of? tlie trough and the v bottoni or inner periphery of the ring for the purpose oi centering the ring, the diameter of the composite inner element thus provided being auch that the inner element can be dropped into the outer element with the material to he treated placed on the periphery of the former, but when the mold is heated the inner element will expand su'iin ciently to force the material against the opthan that of the outer member, a supporting element of harder metal having a peripheral trough to receive the ring of softer metal7 the trough being of such depth that its hottoin is free of the hot-torn or inner periph ery of the ring', the said ring and trough heing made an easy fit at that part of the side ivalls which is near the outer periphery of vthe ring hut a loose lit from siichpart to the inner periphery of the ring and ineans for' '.eenteiing the the diameter of e composite inner element .bling radially in the trough,

thus provided heiag such that the inner element can be dropped into the outer element with the material to he 'ti'eatesoliced onv the i periphery of the former, hat when the meid is heated the inner element will expand siii'lieiently to the material against the op posing iace oic the outer element, substantially forth.

in 'testimony whereof ll have signed ray naine to this specification in the presence of two subscribing witnesses.

THGMS SLQE y itnesses:

A. M. rivivnne? RONALD S. ioiiiin; 

